In the future, Tokyo has fallen victim to syndicates, trigger-happy people who run rampant and other groups who don't like to follow the rules. In response, an organization called RAPT has been created, whose goal is to maintain their definition of "peace". In the underground, however, science involving humans and powerful mechanics is progressing at a steady phase, but for what purpose? Meet our four angels who know how to kick butt and raise hell whenever it's needed. Their motto? Shoot first, talk later. Their mission? To make the seemingly impossible possible, of course...